Integrated assessment of indoor thermal conditions and heat exposure effects on public health in Firozabad City of India

Abstract Indoor environmental quality plays a pivotal role in shaping human health and overall well-being, yet its influence remains underexamined in heat-intensive industrial cities such as Firozabad. The central problem addressed in this study is the persistent indoor heat exposure and inadequate thermal comfort conditions in residential areas located near the glass and bangle manufacturing clusters, where elevated temperatures may exacerbate health risks. The objective of this research is to evaluate indoor thermal conditions, quantify their relationship with self-reported health outcomes, and develop a multiscale assessment framework that identifies spatial variations in vulnerability across the city. A mixed-method methodological approach was employed, integrating indoor microclimate monitoring, household surveys, thermal comfort modelling, and GIS-based spatial assessment. Correlative analyses were conducted to examine the association between thermal indicators and symptom prevalence among residents. Findings reveal statistically significant correlations (p < 0.01) between elevated indoor temperatures, insufficient daylight access, and increased occurrence of heat-related ailments, with correlation coefficients ranging from r = 0.563 to 0.827. Spatial disparities were further evaluated using a standard-score (Z-score) additive model to generate composite vulnerability indices, highlighting neighbourhoods with the highest exposure and health burden. The study underscores the urgent need for evidence-based urban and building-level interventions aimed at mitigating indoor heat stress in industrial environments. Policy implications include the prioritization of passive cooling strategies, improved building design regulations, and targeted public health measures to enhance thermal comfort and reduce heat-related health risks in Firozabad’s high-temperature urban zones.